The general goal of these investigations is to elucidate mechanisms of solute transport in the membranes of liver mitochrondria and the relationships between these mechanisms and processes of cellular metabolism. Specifically, some investigations would focus on the energy-linked uptake of inorganic cations by mitochondria. The kinetics of 42K flux into rat liver mitochondria would be examined in relation to a proposed non-electrogenic transport mechanism. In addition, genetic dissection of the cation transport mechanism and its relationship to energy-conserving reactions would be attempted, using yeast mitochondria as a model system. Other experiments would examine the mechanisms by which 14C-labeled amino acids are transferred across the membranes of liver mitochondria. The possibility that the mitochondrial membrane barrier may control rates of amino acid metabolism would be examined.